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Leak Detection Systems Overview
Operating Principles of Leak Detection Systems
Container Design
Liquid / Gas Medium
   ASF Leak Detector Type D9 R325 / D9 R255 - Pressure Principle - Overview

   General Design Permit (DIBT) No. Z-65.23-109 (Tested by TÜV Nord, Hamburg)
   Type D9 R325 - Article No.: 4141 0049 / Type D9 R255 - Article No.: 4141 0055

Print Version

  • To monitor double-walled tanks.
  • Container types according to DIN EN 12285-1 (DIN 6608 Part 2), DIN EN 12285-2 (DIN 6616 Form A), DIN 6619, Part 2, DIN 6623, Part 2, DIN 6624, Part 2.
  • No permeation may pass through the inner tank wall into the interstitial space.
  • Non-standard containers with a general building inspectorate approval.
  • For monitoring of water-polluting liquids, including flammable liquids with a flash point < 55°C.
  • The storage medium must not exceed the density allowed for the container.
  • The leak detector can be used for monitoring one or several underground tanks utilizing an appropriate manifold system.

The leak detector must be mounted outside the hazardous area (ex-zone)!

  • Leak detector according to the principle of positive pressure with integrated pump and pressure relief.
  • The outside air is sucked through a vessel with dry beads (air dryer), which dries the air down to a relative humidity of <10%.
  • The saturation of the dry beads, depending on the humidity, is reached in about 12-15 months, identifiable by the color change, - initially orange - colorless at saturation.

Operating Pressure
in the interstitial space < 490 mbar

Switching Values: relative pressure

Type D9 - 255
Alarm ON PAE = 255 mbar +30/0 mbar
Pump OFF PPA = ca. 360 mbar +/-15 mbar
Overpressure valve OPEN PSV < 400 mbar

Type D9 - 325
Alarm ON PAE = 325 mbar +30/0 mbar
Pump OFF PPA = ca. 450 mbar +/-15 mbar
Overpressure valve OPEN PSV < 500 mbar

For further data please see the Technical Description of the D9 leak detector.

Operating Conditions
  • The interstitial space of the container must be designed for the max. operating pressure of the leak detector.
  • For Type D9-255: Alarm switching value (255 mbar), allowed operating pressure in the interstitial space minimum 0,4 bar.
    For Type D9-325: Alarm switching value (325 mbar), allowed operating pressure in the interstitial space minimum 0,5 bar.
  • Leak detection fluid may not be present in the interstitial space of the container.
  • The containers must be operated pressureless.
  • Appropriate manifolds together with a D9 leak detector may only be used for monitoring underground tanks.

  • Installation of a potential free relay
  • Installation in protective casing with exterior alarm and heating. (See product image)

Dryer / Drying Beads

Underground tanks = 180 cm³
Aboveground tanks:

Mounting Examples

Please click on the picture for a larger view!

  Product Images

Leak detector D9 R325 with new design
Leak detector D9 R325 / D9 R255
featuring the new improved design

Previous Leak Detector Type D9 - in protective casing with heating unit
Previous Leak Detector Type D9
In protective casing with heating unit

Technical Description D9 R325 und D9 R255Technical Description D9 R325
Data Sheet D9Data Sheet D9
General Design Permit (DIBT)General Design Permit (DIBT)
D9 R325 AccessoriesD9 R325 Accessories & Assembly Kits
Produktbild hochauflösendProduktbild D9 hochauflösend (1000x1000 px, 300 dpi)

Advantages of the new design of the ASF leak detection systemsAdvantages of the new design of the ASF leak detection systems


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